Sansui Sled2453w No Standby Set Is Dead

[Sinfury2112]

Hello,
Trying to fix this set for friend of mine there is no standby light at all he said heard pop and quit working. Fuse is good I found a blown 0.22 ohm resistor replaced that now have 170v across main cap he purchased new mainboard from ebay but the prob lies in the psu somewhere cant find schematics anywhere what I think is the startup cap 50v 22uf has 10v across it any help would be much appreciated here is pics of the psu below thanks for looking P.S also tested large diodes and mosfet out of the board tested okay tested all smaller diodes in board tested okay

[CapLeaker]

Re: Sansui Sled2453w No Standby Set Is Dead

Sorry... you got to make better pics than that. Everything is just a big blurr.

[Sinfury2112]

Re: Sansui Sled2453w No Standby Set Is Dead

Sorry... you got to make better pics than that. Everything is just a big blurr.

Here Are Clearer Pictures I Hope This Helps

[CapLeaker]

Re: Sansui Sled2453w No Standby Set Is Dead

Not really... those are better, but I still can't read not a thing. Be careful there are lethal voltages in the primary circuit. Plug the PSU in and see what you get on the main filter cap.

[Sinfury2112]

Re: Sansui Sled2453w No Standby Set Is Dead

Not really... those are better, but I still can't read not a thing. Be careful there are lethal voltages in the primary circuit. Plug the PSU in and see what you get on the main filter cap.

I get 170v on the cap

[Sinfury2112]

Re: Sansui Sled2453w No Standby Set Is Dead

sorry about crappy photos I think you can read these now LOL my cam really sucks!!

[jetadm123]

Re: Sansui Sled2453w No Standby Set Is Dead

With power disconnected, try checking large transistor Q501 for a short. Really surprised it's not heat sinked.

[Sinfury2112]

Re: Sansui Sled2453w No Standby Set Is Dead

With power disconnected, try checking large transistor Q501 for a short. Really surprised it's not heat sinked.

I tested that mosfet out of the board checked good im stumped well my meter has only 1.6v in the diode test mode so I used a 9v battery to charge the mosfet in the on position does it matter?

[Sinfury2112]

Re: Sansui Sled2453w No Standby Set Is Dead

I think I just found my problem the opt coupler is wide open both sides
2561a is part number

[CapLeaker]

Re: Sansui Sled2453w No Standby Set Is Dead

did you check fuse F501?

[Sinfury2112]

Re: Sansui Sled2453w No Standby Set Is Dead

yep fuse is good thank you

[Sinfury2112]

Re: Sansui Sled2453w No Standby Set Is Dead

it had a resister blown when I first got the set it protected the fuse

[CapLeaker]

Re: Sansui Sled2453w No Standby Set Is Dead

check those black square and blue caps on the primary.

[Sinfury2112]

Re: Sansui Sled2453w No Standby Set Is Dead

there is not any markings on the blue caps if I need to replace them I will try test them best I can I don't have an esr meter

[CapLeaker]

Re: Sansui Sled2453w No Standby Set Is Dead

that long blue cap I mean. you don't need an ESR for those type of caps.

[Sinfury2112]

Re: Sansui Sled2453w No Standby Set Is Dead

on the long blue cap it is reading OL. on all of the Resistance Settings its marked GM 223J 2G S'M08 have no idea what the values are to replace it Im guessing its bad

[CapLeaker]

Re: Sansui Sled2453w No Standby Set Is Dead

That should be a 0.022uF/400V cap. You can't measure a cap like that with your meter in resistance. You have to set your DMM into capacitance (if it has one).

[jetadm123]

Re: Sansui Sled2453w No Standby Set Is Dead

The 10v across the startup cap appears a bit low. It should be connected to the vcc leg of the 8-legged pwm smd chip on bottom of the board. If yes, then try replacing the startup cap and see what happens.

[Sinfury2112]

Re: Sansui Sled2453w No Standby Set Is Dead

the 223j cap measures 23.60nf on meter in cap mode is this bad? the small startup cap measures 23uf and its a 50v 22uf cap

[CapLeaker]

Re: Sansui Sled2453w No Standby Set Is Dead

The 223j is good. For the electrolytic one you'd need an esr meter, to make sure, I doubt it's bad, but can change it and see what's happens